Convert pressure values between bar and atm using exact, standards-based factors. Abbreviations: bar (bar), atmosphere (atm). Both are non-SI units defined in pascals (Pa).
Bars (bar) to Atmospheres (atm) Converter
Enter a value in bars (bar) below and press the button to convert it to atmospheres (atm).
Bars (bar)
Result in Atmospheres (atm)
How to Use
- Enter a value in the bar field.
- Optionally set decimal places.
- Click Convert to get atm. Use Copy to copy the result. The Swap button lets you jump to the reverse direction on a paired page.
Definitions of Measurement Units
Bar (bar) — Non-SI pressure unit accepted for limited use with the SI. Defined exactly as 100 000 pascals (100 kPa). In U.S. customary units, 1 bar = 14.5037738 psi (via 1 psi = 6 894.757 Pa). System: metric (non-SI).
Standard atmosphere (atm) — Non-SI pressure unit defined exactly as 101 325 pascals (101.325 kPa). In U.S. customary units, 1 atm ≈ 14.6959488 psi (via 1 psi = 6 894.757 Pa). System: conventional (non-SI).
Conversion formula
From the exact definitions:
1 bar = 100 000 Pa and 1 atm = 101 325 Pa:
atm = bar ÷ 1.01325; bar = atm × 1.01325.
Source: NIST.
Conversion Table
| bar | atm |
|---|---|
| 0.10 | 0.098692 |
| 0.20 | 0.197385 |
| 0.50 | 0.493462 |
| 1 | 0.986923 |
| 2 | 1.973847 |
| 3 | 2.960770 |
| 5 | 4.934616 |
| 9 | 8.882309 |
| 10 | 9.869233 |
| 20 | 19.738465 |
| 25 | 24.673082 |
| 30 | 29.607698 |
| 50 | 49.346163 |
| 75 | 74.019245 |
| 100 | 98.692327 |
| 150 | 148.038490 |
| 200 | 197.384653 |
| 232 | 228.966198 |
| 250 | 246.730817 |
| 300 | 296.076980 |
Real-World Examples
- Standard sea-level air pressure: 1 atm = 1.01325 bar.
- Espresso brew circuit (industry standard): 9 bar ≈ 8.8823 atm.
- SCUBA cylinder (DIN 200): 200 bar ≈ 197.3847 atm.
- SCUBA cylinder (DIN 300): 300 bar ≈ 296.0770 atm.
- Fuel-rail regulator (common spec): 3.0 bar ≈ 2.9608 atm.
- Laboratory compressed air header (nominal): 6.0 bar ≈ 5.9215 atm.
- Hydraulic test bench setting: 25 bar ≈ 24.6731 atm.
- Paintball HPA tank fill (3000 psi spec): ≈ 206.843 bar ≈ 204.06 atm.
- Beverage CO₂ regulator setting (draft systems, common): 2.0 bar ≈ 1.9738 atm.
- Autoclave sterilization cycle (121 °C program, gauge ~15 psi): ≈ 2.034 bar absolute ≈ 2.007 atm absolute.
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